Selective thin-film removal is needed in many microfabrication processes such as 3-D patterning of optoelectronic devices and localized repairing of integrated circuits. Various wet or dry etching methods are available, but laser machining is a tool of green manufacturing as it can remove thin films by ablation without use of toxic chemicals. However, laser ablation causes thermal damage on neighboring patterns and underneath substrates, hindering its extensive use with high precision and integrity. Here, using ultrashort laser pulses of sub-picosecond duration, we demonstrate an ultrafast mechanism of laser ablation that leads to selective removal of a thin metal film with minimal damage on the substrate. The ultrafast laser ablation is accomplished with the insertion of a transition metal interlayer that offers high electron–phonon coupling to trigger vaporization in a picosecond timescale. This contained form of heat transfer permits lifting off the metal thin-film layer while blocking heat conduction to the substrate. Our ultrafast scheme of selective thin film removal is analytically validated using a two-temperature model of heat transfer between electrons and phonons in material. Further, experimental verification is made using 0.2 ps laser pulses by micropatterning metal films for various applications.

在许多微加工过程中，例如光电器件的3D图案化和集成电路的局部修复，都需要选择性去除薄膜。可以使用多种湿法或干法蚀刻方法，但是激光加工是绿色制造的工具，因为它可以通过烧蚀去除薄膜而无需使用有毒化学物质。然而，激光烧蚀对相邻的图案和基板下面造成热损伤，从而妨碍其以高精度和完整性广泛使用。在这里，我们使用亚皮秒持续时间的超短激光脉冲，演示了激光烧蚀的超快机制，该机制可导致对金属薄膜的选择性去除，而对基板的损害最小。超快激光烧蚀是通过插入过渡金属夹层来实现的，该夹层提供高电子-声子耦合，从而在皮秒级的时间内触发蒸发。这种包含在内的热传递形式允许剥离金属薄膜层，同时阻止对基板的热传导。我们使用材料的电子和声子之间的热传递的两个温度模型，通过分析验证了我们选择性薄膜去除的超快方案。此外，通过对金属膜进行微图案化以用于各种应用，使用0.2 ps激光脉冲进行了实验验证。我们使用材料中电子与声子之间的热传递的两个温度模型对我们选择性薄膜去除的超快方案进行了分析验证。此外，通过对金属膜进行微图案化以用于各种应用，使用0.2 ps激光脉冲进行了实验验证。我们使用材料的电子和声子之间的热传递的两个温度模型，通过分析验证了我们选择性薄膜去除的超快方案。此外，通过对金属膜进行微图案化以用于各种应用，使用0.2 ps激光脉冲进行了实验验证。